The present invention relates to aminocarboxylic acid-terminated polyoxyalkylenes and to a process for their preparation.
Aminocarboxylic acid-terminated polyoxyalkylenes having three or fewer oxyalkylene units are known in the art. Known aminocarboxylic acid-terminated polyoxyalkylene compounds include ethylenebis(oxyethylenenitrilo)tetra acetic acid and ethylenebis(oxyethyleneimino)dimalonic acid.
Known applications for these compounds include use as chelating agents and use in medical diagnostic tests. It has been discovered, however, that aminocarboxylic acid-terminated polyoxyalkylene compositions of the present invention are particularly useful as extreme pressure additives and may be beneficially employed in materials such as hydraulic fluids, automatic transmission fluids, cutting fluids, greases, lubricating oils and other materials wherein maintenance of the fluid's properties under conditions of extreme pressure are desired.
The use of diamine compounds in lubricating compositions, such as cutting fluids, is known in the art. U.S. Pat. No. 4,043,925 to Felton, Jr. discloses a water based liquid for use in cold-forming metal parts which is a solution of a polyalkylene glycol, an extreme pressure additive, an anti-corrosion agent and a defoamer. The extreme pressure additive is a sulfochlorinated fatty acid. An alpha,omega diamine-terminated polyoxyalkylene is disclosed as a possible corrosion inhibitor. Similar diamines are also disclosed by U.S. Pat. No. 3,186,946 to Sluhan and U.S. Pat. No. 2,917,160 to Turinsky. Amino-terminated tertiary polyoxypropylenes are also known as lubricant additives. Other somewhat similar amines are disclosed by U.S. Pat. No. 4,185,485 to Schick et al.
Although these amines have many uses, fluids based on these amines frequently do not perform as well as desired in extreme pressure applications, such as drilling and tapping, and may result in equipment damage. Therefore a composition which maintains good lubricating properties under conditions of extreme pressure offers significant practical advantages over many compositions known in the art.